The International Monetary Fund will refuse to participate in a new bailout for Greece until there is an “explicit and concrete agreement” on debt relief from the country’s eurozone creditors, an IMF official has confirmed.

The governor of the Bank of England is to use a speech on Thursday to try to calm fears that Britain’s financial system could experience a heart-stopping shock following last week’s vote to leave the EU.

Leading London-listed shares have recorded their biggest daily rise since October 2011, regaining all their losses and more since the Brexit vote, with nearly £60bn added to the value of Britain’s top 100 companies.